MIXING OF FERTILIZERS 165 



can mix from 6 to 8 tons per day, weighing out the materials 

 when fractions of a sack are used and assuming the weight 

 on the sack as accurate when full sacks were used. In the 

 formula noted, only the muriate of potash was weighed. 

 The mixed material was replaced in the sacks from which 

 the raw materials were removed. The cost of mixing each 

 ton can be computed by dividing the wages of the men by 

 the number of tons mixed. It will usually amount to less 

 than 50 cents per ton. 



114. Educational Influence. An advantage of the home- 

 mixing of fertilizers, not often considered, is that it necessi- 

 tates a more thorough knowledge of fertilizing materials and 

 it is a strong incentive to study, for fertilizing materials 

 cannot be indiscriminately mixed. However, the incom- 

 patibilities are few and easily explained. The chart, Fig. 

 64, shows the materials that may be mixed advantageously, 

 and the materials that should not be mixed. This chart, 

 which had its beginning in a German publication, has been 

 modified from time to time as data have been secured. It 

 is modified from the chart given in Bulletin 388 of the Office 

 of Experiment Stations, because it has been shown at the 

 South Carolina Experiment Station that the potash content 

 both of muriate of potash and kainit is rendered partly 

 insoluble by mixing with basic slag or Thomas phosphate; 

 and the chart has been made to conform to this fact. 



115. The Calculation of Formulas. Six forms of cal- 

 culations are commonly met with in connection with the 

 home-mixing of fertilizers. 



1. Given the percentage and weights of materials; 

 calculate the formula. 



2. Given the materials and their analyses and the com- 

 position of the formula desired ; calculate the weight of each 

 material required. 



3. Given the materials too low in composition for 

 making a formula of high percentage composition; over- 

 come the difficulty. 



